


Between the Two of Us

by pl2363



Category: Transformers Generation One
Genre: M/M, Oral Sex, Sticky Sex, Twincest, sparklings mentioned
Language: English
Status: Completed
Published: 2013-05-15
Updated: 2013-05-15
Packaged: 2017-12-11 23:46:56
Rating: Explicit
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 3,457
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/804639
Author URL: https://archiveofourown.org/users/pl2363/pseuds/pl2363
Summary: <blockquote class="userstuff">
              <p>Sunstreaker and Sideswipe discover they were created loving one another.</p>
            </blockquote>





	Between the Two of Us

**Author's Note:**

> This started off as a brain dump of random scenes I had rolling around in my head, trying to write them out so I could return to my other lingering fics. So have some brain dump and head canon with a heaping side of smut! :D 
> 
> As per usual, I abuse grammar. Sorry commas and fragments!

_Golden Age, Cybertron-_

The brothers sat on the decking of the balcony attached to their small apartment several stories up, looking out over the city beyond the railing as they each sipped their energon. The night was still and quiet, and the lights of the city shimmered below them.

Sunstreaker’s mind wandered to earlier in the day and an exchange he and his brother had with a fellow warehouse worker. They’d been unloading containers when he asked if they were interested in attending a club with him since they were new in town. He wanted to show them some of the night life Iacon offered. He’d also mentioned how much he needed to find someone to hook up with and “‘face all night”. Neither of them had interfaced before, and Sunstreaker certainly had no desire to interface with a stranger. Sideswipe turned him down with his usual charm, saying maybe next time.

From the moment they’d been sparked, the moment their optics met for the first time, Sunstreaker knew he loved Sideswipe. It was almost impossible to explain. It ran deep. It came from his very spark. A tough sparklinghood filled with trauma after trauma brought them closer together, possibly more so than other twins.

Sideswipe glanced at Sunstreaker. “You believe Rotorgage earlier?” he said, laughing. “Primus, he has no clue how young we are, does he?”

“Nope,” Sunstreaker replied before finishing his energon in a few greedy gulps. 

“We’ve never even kissed anyone before,” Sideswipe said, shaking his head.

Sunstreaker gazed at Sideswipe for a long moment. Truthfully, he’d often come close to initiating a kiss with his brother. It was something he secretly fantasized about. Their creators had dumped them in the care of their city state government when they were small. He still vividly remembered the punishments doled out after they were caught snuggling together in one another’s berths at the group home. The caretakers told them it wasn’t normal. If enjoying being close to his brother wasn’t normal, then wanting to kiss him had to be a freakish level desire to have. He just did his best not to let himself think about it too much.

“Guess we should recharge,” Sideswipe said. He pushed to stand, and offered a hand to help Sunstreaker up.

Taking the hand, Sunstreaker got to his feet. They stood for a moment looking at one another. Sunstreaker sensed his brother wanted to say something. “What is it?”

“Nothing,” Sideswipe replied, grinning.

Sunstreaker narrowed his optics on his brother. “You only say ‘nothing’ when there is definitely _something_. What is it?”

Sheepishly smiling, Sideswipe shrugged his shoulders. “Ever wonder what it would be like?" 

“What are you talking about?” Sunstreaker asked, confused. 

“Kissing. Ever wonder?” Sideswipe had that glint in his optics that Sunstreaker usually associated with his brother’s more mischievous side. 

“Sure I have,” Sunstreaker replied. 

“Want to try it?” Sideswipe stepped close to Sunstreaker. “With me?” 

Heat immediately rippled over his plating. Sometimes he wondered if Sideswipe could read his mind or if they were just so much alike that they’d simply been harboring the same silent thoughts. 

Sunstreaker nodded. 

That adorable lop-sided grin curved Sideswipe’s lips as he reached up and cupped Sunstreaker’s face in his hands. “Then let’s try it out.” 

They leaned in close, and Sunstreaker gently ghosted his lips against his brother’s; curious and wanting this so much his lips practically ached for the contact, but also unsure and fearful they were crossing a line they shouldn’t.   

In classic Sideswipe style, his brother lost his patience and pressed forward without an ounce of hesitation. Their lips molded together perfectly. The warmth and heat that spread over their linked mouths felt more incredible than Sunstreaker imagined it might. Sideswipe parted his lips, pulling Sunstreaker’s apart and their glossae tentatively met between. They caressed one another, twisted around and twinned between their linked, hot mouths. Sunstreaker felt his interface hardware stir from this solitary kiss. Was it wrong, though? To want his brother this way? How could something that felt so right be considered wrong, though? Sunstreaker’s head felt like it was spinning, and he suddenly reared back, breaking the kiss. His vents hitched as stood trembling slightly before his brother. 

Sideswipe’s hands still cupped his face, and he smiled at him. “You have any idea how long I’ve wanted to do that?” 

“Not supposed to want to, though,” Sunstreaker replied.

“But, that felt _right_. Like the way it’s supposed to be between us. Didn’t it?” Sideswipe looked confused by Sunstreaker’s reaction. 

“It did,” Sunstreaker conceded. 

“Who's to say what we’re supposed to do anyway?” Sideswipe pulled Sunstreaker’s face close, and gently nuzzled their noses. “I say we do what we want. We already share a berth, Sunny. Frag everyone else for thinking that’s weird. I love being close to you.” 

Optics dimming, Sunstreaker half-smiled. “I love you, Sides.” 

Sideswipe’s optics brightened then he laughed a little. “Love you, too, you soft-spark.” 

Reaching for his brother, Sunstreaker slipped an arm around his waist, pulling their bodies flush. His brother let go of his face and slid his arms to rest over Sunstreaker’s shoulders as they stared deeply into one another’s optics. 

“I want more than just a kiss,” Sunstreaker whispered. His admission made his face heat up with a touch of embarrassment. 

“Me, too.” Sideswipe’s optics shined brightly. It wasn’t fair that Sideswipe was so handsome, so irresistible. 

How long had his brother been harboring the same feelings, he wondered. Wrong or right blurred as Sunstreaker captured his brother’s lips again in another deep kiss. It felt too good to stop now...

Staggering inside the apartment from the balcony, they continued to kiss while groping each other's plating. Sideswipe grabbed one of Sunstreaker’s hands and pulled him toward the berth. Plopping down, Sideswipe stared up at him, optics darkened in hue with his own arousal. “You’re so pretty. Always thought so.” 

It was like a dam had been broken inside Sunstreaker. Feelings he’d felt but tried to hide from for so long came rushing forward. He wanted to tell Sideswipe how attractive he thought he was, but instead, he bent down and kissed him in reply. Words had never been his strong suit. Action always spoke best for him. 

Sideswipe broke the kiss and slid to lie back on the berth. His interface hardware cover retracted, revealing his onlined spike. Sunstreaker had seen his brother’s spike before, but never like this. He sat down on the edge of the berth and touched it somewhat curiously, running the tips of his fingers over the ridged surface. His own spike surged against the closed cover. Primus, he wanted Sideswipe so much. 

Parting his legs a little, Sideswipe warmly smiled at Sunstreaker. “What are ya waiting for?” 

“Flirt,” Sunstreaker said accusingly as he crawled up onto their berth and got on his hands and knees over his brother. He undid his own cover, spike jutting out and touching Sideswipe’s. Heat once again danced over his plating as he let it sink in what they were doing. What they were about to do. 

“Stop thinking,” Sideswipe said. “I want you, and you want me, right?” 

Sunstreaker looked into his brother’s optics and then nodded. “Yes.” 

Reaching down, Sideswipe moved Sunstreaker’s spike so the head touched his valve’s rim, rubbing it over the already slicked opening. “Please, Sunny.” His brother’s voice took on a needy quality he wasn’t used to hearing very often. It made his spark flutter to be wanted like this. 

Unable to resist, unwilling to stop what felt right to him, Sunstreaker rolled his hips forward, spike pushing inside his brother. He gasped, his sensory net flaring with heat and desire that seemed to tingle over his entire frame. Mesh walls trembled around him, snug and slick. He lowered himself down so their chests pressed together, gazing into Sideswipe’s dark blue optics as slowly withdrew and then pushed back in. Sideswipe moaned, his whole body feeling hot against Sunstreaker’s. 

“More,” Sideswipe said, his voice heady and thick sounding. 

The line was crossed and left in tatters light years away as Sunstreaker expressed his deep love for Sideswipe with his body. They were soon nothing more than a writhing, moaning mass on their berth. Sideswipe’s hands desperately grasped at Sunstreaker’s frame, as they kissed and mouthed one another. Reaching a fever pitch with his rhythmic thrusting, Sideswipe arched under him, groaning and nearly denting his plating as his fingers curled into his sides. Sunstreaker’s rigid spike was squeezed hard by his brother’s valve, causing him to roar as he also overloaded, spike exploding inside his brother. 

After the sharp, lovely sensation of overloading passed, Sunstreaker draped himself over top of Sideswipe. He was left floating in a blissful daze, having had no idea a physical act could feel so amazing. 

Silence enveloped them as they lay there unmoving for a good, long while. What they’d done began to sink in for Sunstreaker. He felt torn between how right this felt to him and what they’d been taught growing up. Often forced to scrub floors in the washracks when caught together in a berth recharging, or else smacked when they dared to hold hands. 

Sideswipe sighed loudly, interrupting his thoughts. Letting air hiss from his intakes, he gave Sunstreaker a weak hug with one arm. “That was awesome. Can’t wait to do it again.”

It appeared his brother had no such reservations about what they’d done. Sunstreaker tipped his head up, pressing a kiss to his brother’s chin. “We probably shouldn’t tell anyone about this.” 

“Hm. You’re probably right,” Sideswipe agreed, though he sounded a little disappointed. 

“We’ve been put through enough slag.” Sunstreaker shifted his hips, slipping free and then curling up against his brother’s side. 

With a happy grin on his face, Sideswipe looked at him and nodded. “It’ll be between you and me, like always.” 

“Like always,” Sunstreaker replied. 

… 

_Beginning of the war, Cybertron-_

“This is stupid,” Sunstreaker mumbled. 

“That old mech, Kup, gave us an ultimatum for breaking into the warehouse: Join the Autobots or be jailed indefinitely,” Sideswipe replied. 

Sunstreaker frowned. They’d been caught stealing rations. Hunger and desperation in this time of war drove them to it, though. Somehow that old mech convinced them to join up and took them to the recruitment office. Once they’d been identified and put into the system, they’d been dragged to the medical center on base to be examined. Sunstreaker hated medical centers. Hated medics. They’d both spent a great deal of their early sparklinghood being probed and prodded because of their unusual sparks. Now here they sat, side by side on this berth waiting to be poked and prodded all over again. 

The medic entered the room, frown on his face as he stared at a datapad. “I’m Ratchet.” 

Grip tightening on the edge of the berth, Sunstreaker steeled himself. Just being here was putting him on edge. 

“Heya doc,” Sideswipe replied. 

Ratchet glanced up from the datapad, optics darting between them. “Twins, huh?”

“Nah, we just pretend to be to make medics give us funny looks,” Sideswipe replied with a lop-sided grin. 

“And smart-afts, too? My lucky day,” Ratchet replied, laying on the sarcasm.

Sunstreaker heaved a sigh. He just wanted this over with so they could get the slag out of here.   

“According the records I managed to dredge up, you are fraternal twins.” Ratchet tapped his datapad, clearly marking down notes of some kind. “Your records are outdated. Looks like you haven’t been to a medical center since _well_ before the war.”

“No offense, but me and Sunny sort of despite medics,” Sideswipe replied.

“ _Sides_ ,” Sunstreaker hissed. 

“I don’t blame you.” The medic continued to type into the datapad. “You’re exceedingly rare among a rare class of sparks. I’m sure you both had a pretty traumatic sparklinghood.” 

“What’s with all the typing?” Sideswipe asked, craning his head up to try and see. 

Ratchet vaguely frowned. “I don’t mean this to come off as blunt, but I need to know if you two are actively interfacing?” 

Sunstreaker’s gaze sharpened on Ratchet. “That’s none of your business!”

The medic shot a pointed look at Sunstreaker.

“ _Sunny_ ,” Sideswipe said, reprimand in his voice. “You kidding, doc? Two handsome mechs like us? Of course we get lots of action.”

Setting the datapad down on the berth, Ratchet crossed his arms over his chest. “I meant with one another.” 

“No way!” Sideswipe said, nervously laughing. “We’d never do that!”

“Do you know why your sparks are exceedingly rare?” Ratchet asked, looking at Sideswipe.

His brother shrugged his shoulders. “Not like medics told us much. We were more like science projects to them.” 

Ratchet frowned. “Look, split spark twins are true twins, sharing a core. Being fraternal means you’re brothers with different coding and separate cores like any other siblings.” Ratchet glanced between them. “In your case, though, your sparks were stuck together when you were created and pulled apart to be put into your individual frames. Due to your spark’s time attached to one another, a spark bond was created. Every fraternal twin set I’ve seen documented interface and engage in a relationship like any bonded couple will. It’s just how it is.” 

“No one told us _that_ part before,” Sideswipe replied, with bright optics. 

“I’ll take that as a yes,” Ratchet replied, picking the datapad back up and continuing to tap notes into their records. 

Bonded from the moment they onlined... That explained _so_ much about the feelings Sunstreaker had always harbored for his brother. A part of him seethed with anger and resentment for how they’d been treated in that group home. Made to feel bad for feelings they had no control over. 

Sunstreaker narrowed his optics on Ratchet. “Even so, it’s not accepted behavior, is it?”

The medic dimmed his optics. “Sadly, it’s not. But I will make sure you are both assigned to the same units and always in cohabitation quarters. If anything happens, though, don’t hesitate to come to me with it.” 

“Like if some nosy aft sees us and tries to give us a hard time?” Sideswipe asked. 

Ratchet’s dour frown faded to a small smile. “Yes, but you need to understand barracks are cramped spaces. Try and be discreet. It’ll save you both a lot of grief.” 

“You gonna tell whoever we get for a CO?” Sunstreaker asked.

Shaking his head, Ratchet replied. “This is a medical issue and stays between us.” 

… 

_Now, Earth-_

“Then I told him, my rotors were worn, I need new ones. Know what he said?” Gears asked as he stood with Brawn in front of the energon dispenser in the refectory, yapping away. 

Sunstreaker stood impatiently waiting for them to move with his arms crossed over his chest, glaring at them. He just got off shift and was not in the mood for this slag. It didn’t help that he not only despised minibots, but after almost four weeks stuck on opposing schedules from Sideswipe, his tolerance levels for stupidity were at an all time low. Since the shift switch, he’d not gotten a decent night’s rest, not to mention when he wasn’t able to regularly interface every little thing irritated him even more than usual. _Especially_ ‘little’ things like minibots.

“Why don’t you just oil them?” Brawn asked. “That’s what I do when they squeak.” 

Ready to snap, Sunstreaker narrowed his optics on them. “If you two don’t move in the next three seconds I will toss you both out of my way.” Sunstreaker practically growled at them. 

Gears and Brawn both looked up at him with wide optics. 

“Oh, hey there! Sorry ‘bout that, Sunstreaker. Didn’t see ya,” Brawn stepped aside, pulling Gears with him. 

How in the name of Pit had they not seen him? He was twice their size and painted racing yellow. Were they so old their optics were fritzing? 

“Yeah, you’re well above of our line of sight,” Gears said, chuckling. 

Sunstreaker grunted at them after getting his serving and then quickly left the refectory, not feeling up to being around anyone right now. He missed his brother with a deep ache that radiated from his spark. He needed more than the one hour a day their shifts allowed them to be together. Frown etched on his face he passed the corridor that led to medbay and the labs. He came to a halt, knowing that Ratchet had intervened on their behalf before. Maybe he could talk some sense into Prowl and get them off this horrible opposing schedule? 

He turned down the corridor and entered medbay. “Ratch?” 

Emerging from his office, Ratchet raised an optic ridge at Sunstreaker. “Bribing me?” 

“Huh?” Sunstreaker canted his head. 

“The energon,” Ratchet said, pointing. 

“Oh, I just got off my shift. It’s for me,” Sunstreaker replied.

Ratchet crossed his arms over his boxy chest and heaved an annoyed sigh. “What do you want?”

To the point, as usual. One of the reasons Sunstreaker had grown to like Ratchet over the eons. “Just wondering if you could maybe get Prowl to switch me and Sides back to the same schedule again? We haven’t had any time off at the same time in almost a month. I’m about to snap.” 

“You’re always about to snap,” Ratchet replied with a wry smile. “But, I’ll see if I can get the task master to switch you guys back around.” 

Sunstreaker sighed. “Thanks.” 

“Next time, better bring me an actual bribe,” Ratchet replied. 

“What? My smiling face isn’t enough?” Sunstreaker grinned. 

Ratchet actually laughed a little as he shook his head.

… 

Glossa lapping over his spike, Sunstreaker quietly moaned. Sideswipe eagerly took it into his mouth, suckling the head as he glanced up. Lying in his berth with Sideswipe between his legs, lavishing his spike with some much needed attention was just what he needed. 

Prowl had switched their shifts back. For the first time in a month, Sunstreaker got a full night’s rest with Sideswipe curled up beside him the berth. They’d just woken to their first shared day off in almost three months, and Sideswipe wanted to celebrate, which of course meant ‘facing. 

Sunstreaker shivered as Sideswipe continued to bob his head over his spike and squeeze the base, pumping it with his hand. 

“Gonna overload. Better stop...” Sunstreaker whined. 

His brother didn’t stop. Not that he was surprised. A few more hard squeezes and Sunstreaker was unable to hold back, mouth agape in a soundless moan as he stiffened and his spike unloaded into his brother’s delightful mouth. 

After a moment, Sideswipe lifted his head up, licking his lips and then grinning as they locked gazes. “Not bad for an opener.” 

“Opener, huh?” Sunstreaker asked with a half-smile. 

Mischievous grin curving his mouth, Sideswipe moved with speed, laying himself over top of Sunstreaker with his own spike nudging into the entrance of his valve. They engaged in a brief kiss before Sideswipe impaled Sunstreaker in one hard thrust. 

Sunstreaker groaned and Sideswipe wrapped a hand over his mouth to stifle him. “We’re supposed to be quiet, Sunny.” 

Right, quiet. It was hard to not make noise when his brother was so good at turning him into a quivering pile of parts, though. 

Slowly at first, Sideswipe rocked his hips pushing in and out of Sunstreaker’s valve. He kept his hand over Sunstreaker’s mouth and smiled as he watched the reactions to his hard thrusts. Sunstreaker’s optics flickered and his hands grasped at his brother’s back, fingers clawing at the smooth plating. His brother’s style of interfacing was always so intense. In no time Sunstreaker was moaning into his brother’s fingers, writhing beneath him as he was pushed closer and closer with each roll of Sideswipe’s hips. 

Keening, he contorted with his surging overload. Sideswipe traded his hand for his mouth, muffling the ensuing cry of release with a desperate kiss. Sideswipe gasped, breaking the kiss as cycled mech fluid flooded Sunstreaker’s valve. Sideswipe shivered over him, doing his best to stifle his own groaning. It sort of sucked slag they had to be so careful about not making too much noise, but at this moment, Sunstreaker could care less. He’d missed his brother so much over the last few weeks. He especially missed sharing moments like this with him, raw and vulnerable to one another, exposing a shared love that was impossible to ignore. 

Sagging his weight over Sunstreaker, Sideswipe sighed air from his intakes in a hiss. “Missed you.” 

Sunstreaker chuckled. “Missed you, too.”

Lifting his head up, a lop-sided grin curved his brother’s lips. “I say we stay in this berth all day long, ‘facing each other until we can’t move. What do ya say?”

“Won’t hear me complaining,” he replied, grinning back.


End file.
